Recent developments on Monolithic Active Pixel Sensors (MAPS) for charged particle tracking. Outline...
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Transcript of Recent developments on Monolithic Active Pixel Sensors (MAPS) for charged particle tracking. Outline...
Recent developments on Monolithic Active Pixel Sensors (MAPS) for charged particle tracking.
Outline• The MAPS sensor (reminder)• MIMOSA-22, a fast MAPS-sensor• The SUZE-1 FEE chip• Random Telegraph Signal and radiation damage• Summary and Conclusion
Michael Deveaux on behalf of IPHC Strasbourg, IKF Frankfurt/M
(Irradiations: F.M. Wagner, MEDAPP, FRM II reactor Munich)
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 2
The operation principle of MAPS
Reset+3.3V+3.3V
Output
SiO2 SiO2 SiO2
N++ N++N+ P+
P-
P+
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 3
How to build fast MAPS for the MVD: IPHC Strasbourg
Sensor array
Discriminators On - chip zero suppression
Bonding pads + output Amplis.
Pixel column
Readout busExpected time resolution: ~10 µs (~100 kFrame/s)
MIMOSA-16 and 22 SUZE-1
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 4
Last years status: MIMOSA-16
32 col. of 128 pixels (25 μm pitch, integrated CDS )1 Discriminator/column
Tests at CERN-SPS ( 180 GeV pi−) in Summer 2007
Threshold: 6 mV Detection efficiency: 99.88 ± 0.05 (stat) % Fake rate: <10−5 Spatial resolution: 4.6 μm
Proof of principle for MAPS with on-pixel CDS and on-chip discriminator (small size only).
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 5
MIMOSA-22, a fast and big chip
MIMOSA – 22:
• Test the MIMOSA-16 concept with higher surface32 cols x 128 pixels => 128 cols x 576 pixels
• 17 different (improved) pixels designs:New high gain / low noise pixelsRadiation hard pixels
Build smaller pixels18.4 μm instead of 25 µm
Read-out time 100 μs ( 104 frames/s )• JTAG slow control• Programmable test DACs for disciminator tests• 40 MHz digital data output
Tested with Fe-55 source and CERN 100 GeV/c pion beam
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 6
Test results of the new preaplifyers
Noise: • 10 < N < 14 e− ENC + 5 e− ENC Fix pattern noise (individual pixel offset)• Rad hard: 1e− ENC more than standard versionCCE : • 3x3 pixels : 70 – 80 % • 5x5 pixels : 80 – 90 %
Standard SB-Pixel design (Mimosa-16):• Successfully used since MIMOSA-4• No dead time• Noise: ~15e- with on-pixel CDS, else ~ 9e-
New inMIMOSA-22
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 7
Beam test results of MIMOSA-22
Discriminator Threshold Discriminator Threshold
All pixels of interest show:Detection efficiency: >99.8% Fake hit rate: O(10-4 – 10-5)Spatial resolution: ~3.5 µm (~ Pitch / 5)
Detection efficiency Fake hit rate
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 8
How to build fast MAPS for the MVD
Sensor array
Discriminators On - chip zero suppression
Bonding pads + output Amplis.
Pixel column
Readout bus
SUZE-1
SUZE – 1 data sparsification circuit
• Chip with integrated Ø and output memories (no pixels)• Algorithm:
Step1: find up to 6 series of 4 neighbour pixels / raw in block of 64 cols.Step2: Read-out all blocks, keep up to 9 series of 4 pixels.
• Output memory: 4 x (512x16 bits) taken from AMS I.P. lib.
• Surface: 3.9 × 3.6 mm²
• Test result: Works fine up to 115% clock frequencyCan handle up to 100 hits/frame at 104 frame/s
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 9
Next Step: MIMOSA-26
MIMOSA-22 Sensor
SUZE-1 Ø -suppression
circuit
MIMOSA-26
MIMOSA-26
Pixels + Ø-suppression• Expanded surface:
1152 cols x 576 pixels21.2 x 10.6 mm²18.6 µm pixel pitch
• Expanded data sparsification circuit 18 blocks of 64 columns Max. 9 clusters per row
• Data rate: 80 Mbits/s• Submission November 2008
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 10
Radiation hardness studies
together with
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 11
Random Telegraph Signal
Sig
nal [
AD
C]
Time
Random Telegraph Signal: • Modulation of an output signal between two “quantum levels”. • Random period length.• RTS in MAPS sensors first described by Hopkinson (2000)*
Output signal of two MAPS pixels
RTS may generate fake-hits if amplitude exceeds discriminator threshold.Problem for MAPS being used in HEP – experiments?
D. Doering, Bachelor Thesis
D. D
oeri
ng, B
ache
lor
The
sis
* G.R
. Hopkinson: “R
adiation Effects in a C
MO
S A
ctive P
ixel Sensor”, IE
EE
-NS
S V
ol. 47, No. 6, P
. 2480
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 12
Fake hit rate of MAPS with Random Telegraph Signal
Affected SB-pixels remain sensitiv.The fake hit rate of MAPS shrinks with cooling.Identified RTS pixels contribute ~60 – 80 % of all fake hits.
MIMOSA-18 (SB-pixel, irradiated at MEDAPP, FRM II, Munich)
Preliminary
D. D
oeri
ng, B
ache
lor
The
sis
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 13
Distribution of RTS-pixelsD
. Doe
ring
, Bac
helo
r T
hesi
s
Pixel X
Pixel Y Normal Pixel
RTS Pixel
Up to ~10% of all pixels are affected.Masking of pixels is not possible but pixels stay sensitivOperate pixels, tolerate fake hits ( ~ 104 / frame for full MVD)Note: Fast MAPS might show less RTS than MIMOSA-18
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 14
Sensors with improved charge collection efficiency
MIMOSA-Pixelwith 10 x 10 µm²
Standard collection diode( ~ 3 x 4 µm²)
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 15
Sensors with improved charge collection efficiency
How to escapehere?
Bigger collection diodes may improve CCEImproved CCE => improved radiation hardnessTested with MIMOSA-19 (by IPHC)
Diode 1 Diode 2
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 16
Results
A. Büdenbender, Bachelor Thesis
Charge collection efficiency is indeed substantially increased
But the bigger collection diodes generate more noise
T= -20 °C
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 17
S/N of the sensors
A. B
üden
bend
er, B
ache
lor
The
sis
Both MIMOSA-18 and MIMOSA-19 seem fairly radiation hardBig diodes have no advantages because of high noise
Insufficient S/N
M. Deveaux, 12th CBM Collaboration Meeting, 13 - 18 Oct. 2008 JINR Dubna, Russia 18
Summary
At IPHC, a first sizable chip with column parallel readout was producedand tested in the CERN – SPS pion beam:Features: • reduced noise 15 e- => 10 – 14 e- , det. eff. > 99.8 %• pitch 18.4 μm, resolution = 3.5 µmAn FEE chip with cluster finding circuits (SUZE-1) was successfully tested.
MIMOSA-26 integrating the full discrimination chain will be submittedin November.
Radiation hardness tests were undertaken at IKF:
A radiation hardness of 1013 neq/cm² has been shown for two pixel concepts
The effect of Random Telegraph Signal was identified as dominating sourceof background hits in MAPS
Studies on RTS suggest, that RTS can be tolerated if chips are cooled